Urge Flow Rear Rotors Experience
05-09-2016, 04:54 PM
#11
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Measured the same way, for me a vented 2-piece rear was good for roughly 200 degrees rotor temp reduction on XP8s. My vented rotors were larger than the Urge model, though, so that all adds up. As some of the vendors have correctly claimed, doing this mod also seems to improve the ability of the fronts to withstand fade towards the end of the session (you don't lose the rears as the session progresses, so the fronts don't end up trying to pick up the slack). 360 degrees is totally manageable, so looks like the Urge rotor is big enough for your use. 
What are the dimensions of you rear 2pc rotor?
05-11-2016, 09:12 AM
#12
Originally Posted by thomsbrain' timestamp='1462814574' post='23961338
Measured the same way, for me a vented 2-piece rear was good for roughly 200 degrees rotor temp reduction on XP8s. My vented rotors were larger than the Urge model, though, so that all adds up. As some of the vendors have correctly claimed, doing this mod also seems to improve the ability of the fronts to withstand fade towards the end of the session (you don't lose the rears as the session progresses, so the fronts don't end up trying to pick up the slack). 360 degrees is totally manageable, so looks like the Urge rotor is big enough for your use.
What are the dimensions of you rear 2pc rotor?
05-11-2016, 05:24 PM
#13
Thanks for the data. I would guess that actual running temps would vary more on the knuckle and hub but it really comes down to where the measurement was taken and all that. There is going to be heat retained in the hub no matter what just from the hub and bearing doing it's thing when coming off the track.
As others have mentioned the rears get very hot, usually hotter than the fronts, the front brakes do a lot of the work but the moment the rears are no longer contributing effectively the front workload goes up significantly. Awesome to see many people consistently getting better wear rates on the fronts when changing out to vented rear rotors.
As others have mentioned the rears get very hot, usually hotter than the fronts, the front brakes do a lot of the work but the moment the rears are no longer contributing effectively the front workload goes up significantly. Awesome to see many people consistently getting better wear rates on the fronts when changing out to vented rear rotors.
05-11-2016, 06:03 PM
#14
It was great that you took the extra effort to do a back-to-back test of the rotors. The Urge rears with Girodisc/PFC/StopTech 2-piece fronts and stock calipers seems like a great track setup.
You would never notice the weight change in the rotor. If you were racing a competitive Sprint Cup at Daytona or F1 it would still be hard to measure it meaningfully. Cup cars use really light rotors at Daytona and Talladega.
The temperature difference is significant, partly because the other readings were pretty consistent. However, brakes cool off VERY quickly after application. The best low cost way to measure rotor temps is with a temp paint, readily available, not terribly expensive.
There three paints I know of. The Genesis paint is about $80 (if you were nearby you could borrow a bottle) and shows different temperature ranges by changes in color. The colors can be a bit similar and usually have 100F-180F differences between the colors depending on the temperature range. The resolution is adequate for most brake measurements.
Tempilaq has paints that turn at specific temps, and are available in 50F increments in the highest range of the Genesis paint, and 25F in its lowest. It is also available up to 1900F where the Genesis reaches its final at about 1250F, which is below many pads. It is $25 per bottle with each bottle giving only one temp. At least one site has a three bottle set, but with a broad range (250F between bottles).
Links with picks are below along with Alcon and AP pages on reading the temps.
The third is a strip put on the caliper that reads temps there. The range is much lower, peaking under 600F, with under 400F considered preferable: https://www.alconkit...-strips-detail.
If you have data acquisition, there are sensors that ride on the rotor giving a direct reading over time. In contrasts, the paints only provide the peak reading.
The DTC30 is rated for 100F-800F. The DTC70 for 800F-1200F and the DTC60 for 700F-1100F. The newer DTC50 should be ideal, long wearing, good modulation, and a range of 500F-1100F. However, it doesn't appear to be available for Honda calipers (or many race calipers.) http://www.hawkperfo...IDE_FINAL_2.pdf
https://www.pegasusa....asp?RecId=4974
https://www.pegasusa...sp?Product=3161
http://www.tempil.co...cating-liquids/
http://www.raceshopp...ure_paint.shtml
https://www.alconkit...mperature-paint
https://www.alconkit...-800-deg-detail
https://www.apracing...6&ProductID=976
You would never notice the weight change in the rotor. If you were racing a competitive Sprint Cup at Daytona or F1 it would still be hard to measure it meaningfully. Cup cars use really light rotors at Daytona and Talladega.
The temperature difference is significant, partly because the other readings were pretty consistent. However, brakes cool off VERY quickly after application. The best low cost way to measure rotor temps is with a temp paint, readily available, not terribly expensive.
There three paints I know of. The Genesis paint is about $80 (if you were nearby you could borrow a bottle) and shows different temperature ranges by changes in color. The colors can be a bit similar and usually have 100F-180F differences between the colors depending on the temperature range. The resolution is adequate for most brake measurements.
Tempilaq has paints that turn at specific temps, and are available in 50F increments in the highest range of the Genesis paint, and 25F in its lowest. It is also available up to 1900F where the Genesis reaches its final at about 1250F, which is below many pads. It is $25 per bottle with each bottle giving only one temp. At least one site has a three bottle set, but with a broad range (250F between bottles).
Links with picks are below along with Alcon and AP pages on reading the temps.
The third is a strip put on the caliper that reads temps there. The range is much lower, peaking under 600F, with under 400F considered preferable: https://www.alconkit...-strips-detail.
If you have data acquisition, there are sensors that ride on the rotor giving a direct reading over time. In contrasts, the paints only provide the peak reading.
The DTC30 is rated for 100F-800F. The DTC70 for 800F-1200F and the DTC60 for 700F-1100F. The newer DTC50 should be ideal, long wearing, good modulation, and a range of 500F-1100F. However, it doesn't appear to be available for Honda calipers (or many race calipers.) http://www.hawkperfo...IDE_FINAL_2.pdf
https://www.pegasusa....asp?RecId=4974
https://www.pegasusa...sp?Product=3161
http://www.tempil.co...cating-liquids/
http://www.raceshopp...ure_paint.shtml
https://www.alconkit...mperature-paint
https://www.alconkit...-800-deg-detail
https://www.apracing...6&ProductID=976
05-11-2016, 07:43 PM
#15
I've got two track days on my Urge Flow rotors. So far, no complaints. I am coming from a Wilwood rear setup that used a bigger 2-piece rotor and a 4-pot caliper, so saying there is an improvement is going to be a long term thing. The quality and fitment is excellent as you'd expect and I got my e-brake back... I missed that thing so damn much! Also, the Wilwood setup added more piston area, so I have a better feel in the pedal again.
I am running a set of Cobalt XR4 in the rear as a buddy got them for me from his work for fairly cheap (running Hawk DTC-70 up front on some StopTech brakes). I had to block sand them with some 40 grit paper (2mm a pad) to get them to fit, but it was pretty easy. The pads are wearing a little quicker, it seems, but that isn't a review on the rotor. It's a smaller pad on a compound I've never used, so I may end up trying a few different pads as they need replaced.
That said, I have no temp measurements. What I do know is that with my stock, solid rotors, I had to re-tighten my lug nuts after every session (after they cooled) as they would loosen in the rear. Now I just torque the lug nuts in the morning and run them all day.
As usual, Patrick is my favorite to deal with. In my many, many years of buying parts, he's my #1 go-to. In fact, I buy parts for my STi from him if he's a dealer of said brand.
I am running a set of Cobalt XR4 in the rear as a buddy got them for me from his work for fairly cheap (running Hawk DTC-70 up front on some StopTech brakes). I had to block sand them with some 40 grit paper (2mm a pad) to get them to fit, but it was pretty easy. The pads are wearing a little quicker, it seems, but that isn't a review on the rotor. It's a smaller pad on a compound I've never used, so I may end up trying a few different pads as they need replaced.
That said, I have no temp measurements. What I do know is that with my stock, solid rotors, I had to re-tighten my lug nuts after every session (after they cooled) as they would loosen in the rear. Now I just torque the lug nuts in the morning and run them all day.
As usual, Patrick is my favorite to deal with. In my many, many years of buying parts, he's my #1 go-to. In fact, I buy parts for my STi from him if he's a dealer of said brand.
05-11-2016, 08:03 PM
#16
This is why we went with a larger rotor and the RX8 Caliper which has a larger throat. You want directional curved vanes and a wide air gap to pull heat from the rotor, as well as increasing thermal load of the rotor. You just can't fit this in a stock caliper no matter how much grinding you do. Also by increasing diameter to 314mm we've increased mechanical leverage, for a much more responsive setup. The old stock caliper is really really limited with what you can do, moving to a new caliper opens up all sorts of avenues for rear brake performance.
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SAKEBOMB GARAGE > Click here to contact Us
Check some of our most popular products for the S2000:
- Ohlins DFV Billet Lower Mount
- Rear BBK RX-8 Caliper Conversion
- Front BBK AP Competition
- Setrab Oil Cooler Kit
05-12-2016, 05:27 AM
#17
My Wilwood rotor was bigger, narrow-non-directional vaned, and had more piston area and I wouldn't say that you really need that additional leverage. There doesn't seem to be a cooling issue with the narrow spacing and the pad wear is low in the rear of these cars, so taking a little material off isn't that big of a deal. Every compound I've wanted to try has also been available as well.
Not sure what to address on the "responsive" setup. I've never felt any of my brake configurations weren't responsive and they all stopped the car on track, over and over again. Almost all of the fast guys I know running near or at lap record times, all run stock rotors... They just run hot. Now if we were talking about the front brakes (specifically this car), I'd agree on all the points.
Not sure what to address on the "responsive" setup. I've never felt any of my brake configurations weren't responsive and they all stopped the car on track, over and over again. Almost all of the fast guys I know running near or at lap record times, all run stock rotors... They just run hot. Now if we were talking about the front brakes (specifically this car), I'd agree on all the points.
05-12-2016, 08:24 AM
#18
Registered User
This is why we went with a larger rotor and the RX8 Caliper which has a larger throat. You want directional curved vanes and a wide air gap to pull heat from the rotor, as well as increasing thermal load of the rotor. You just can't fit this in a stock caliper no matter how much grinding you do. Also by increasing diameter to 314mm we've increased mechanical leverage, for a much more responsive setup. The old stock caliper is really really limited with what you can do, moving to a new caliper opens up all sorts of avenues for rear brake performance.
05-12-2016, 05:06 PM
#19
This is why we went with a larger rotor and the RX8 Caliper which has a larger throat. You want directional curved vanes and a wide air gap to pull heat from the rotor, as well as increasing thermal load of the rotor. You just can't fit this in a stock caliper no matter how much grinding you do. Also by increasing diameter to 314mm we've increased mechanical leverage, for a much more responsive setup. The old stock caliper is really really limited with what you can do, moving to a new caliper opens up all sorts of avenues for rear brake performance.
05-13-2016, 05:06 AM
#20
Originally Posted by SakeBomb Garage' timestamp='1463025796' post='23964288
This is why we went with a larger rotor and the RX8 Caliper which has a larger throat. You want directional curved vanes and a wide air gap to pull heat from the rotor, as well as increasing thermal load of the rotor. You just can't fit this in a stock caliper no matter how much grinding you do. Also by increasing diameter to 314mm we've increased mechanical leverage, for a much more responsive setup. The old stock caliper is really really limited with what you can do, moving to a new caliper opens up all sorts of avenues for rear brake performance.
https://www.s2ki.com/s2000/topic/949...g/page__st__25